Objective: This study aimed to evaluate the effects of attachment design on maxillary molar distalization and simultaneous expansion during distalization, and the influence of third molars on distalization in the clear aligner technique using the finite element method. Methods: Six models were created to evaluate three different attachment designs on the second molars. Model I: employed a vertical rectangular attachment; Model II: used a vertical rectangular attachment with the presence of the third molar; Model III: used a combined semi-elliptical attachment; and Model IV: featured an opposed semi-elliptical attachment with buccal and palatal components. Models I through IV focused on distalization.Models V and VI were created by adding expansions to Models III and IV. The displacement amounts, clear aligner deformations, and stress distributions were analyzed using Ansys 19.2. Results: The presence of a third molar reduced maximum total displacement by 17%. Models I and III demonstrated similar distal displacement and tipping, both of which were more pronounced than in Model IV. Model IV achieved the most parallel tooth movement, with the least distal and buccal tipping and minimal distopalatal rotation. In the comparison of Models V and VI, Model VI exhibited greater distal and buccal displacements and more tipping than Model V. Conclusions The presence of a third molar reduced distalization efficiency and increased clear aligner deformation. For both movements, the attachment that provided the most parallel movement showed the least displacement. When selecting attachments, it is essential to consider factors such as tooth rotation, inclination, bone support, and root health.

Objective: This study aimed to evaluate the effects of attachment design on maxillary molar distalization and simultaneous expansion during distalization, and the influence of third molars on distalization in the clear aligner technique using the finite element method. Methods: Six models were created to evaluate three different attachment designs on the second molars. Model I: employed a vertical rectangular attachment; Model II: used a vertical rectangular attachment with the presence of the third molar; Model III: used a combined semi-elliptical attachment; and Model IV: featured an opposed semi-elliptical attachment with buccal and palatal components. Models I through IV focused on distalization.Models V and VI were created by adding expansions to Models III and IV. The displacement amounts, clear aligner deformations, and stress distributions were analyzed using Ansys 19.2. Results: The presence of a third molar reduced maximum total displacement by 17%. Models I and III demonstrated similar distal displacement and tipping, both of which were more pronounced than in Model IV. Model IV achieved the most parallel tooth movement, with the least distal and buccal tipping and minimal distopalatal rotation. In the comparison of Models V and VI, Model VI exhibited greater distal and buccal displacements and more tipping than Model V. Conclusions The presence of a third molar reduced distalization efficiency and increased clear aligner deformation. For both movements, the attachment that provided the most parallel movement showed the least displacement. When selecting attachments, it is essential to consider factors such as tooth rotation, inclination, bone support, and root health.

Objective: This study aimed to evaluate the effects of attachment design on maxillary molar distalization and simultaneous expansion during distalization, and the influence of third molars on distalization in the clear aligner technique using the finite element method. Methods: Six models were created to evaluate three different attachment designs on the second molars. Model I: employed a vertical rectangular attachment; Model II: used a vertical rectangular attachment with the presence of the third molar; Model III: used a combined semi-elliptical attachment; and Model IV: featured an opposed semi-elliptical attachment with buccal and palatal components. Models I through IV focused on distalization.Models V and VI were created by adding expansions to Models III and IV. The displacement amounts, clear aligner deformations, and stress distributions were analyzed using Ansys 19.2. Results: The presence of a third molar reduced maximum total displacement by 17%. Models I and III demonstrated similar distal displacement and tipping, both of which were more pronounced than in Model IV. Model IV achieved the most parallel tooth movement, with the least distal and buccal tipping and minimal distopalatal rotation. In the comparison of Models V and VI, Model VI exhibited greater distal and buccal displacements and more tipping than Model V. Conclusions The presence of a third molar reduced distalization efficiency and increased clear aligner deformation. For both movements, the attachment that provided the most parallel movement showed the least displacement. When selecting attachments, it is essential to consider factors such as tooth rotation, inclination, bone support, and root health.

Objective: This study aimed to evaluate the effects of attachment design on maxillary molar distalization and simultaneous expansion during distalization, and the influence of third molars on distalization in the clear aligner technique using the finite element method. Methods: Six models were created to evaluate three different attachment designs on the second molars. Model I: employed a vertical rectangular attachment; Model II: used a vertical rectangular attachment with the presence of the third molar; Model III: used a combined semi-elliptical attachment; and Model IV: featured an opposed semi-elliptical attachment with buccal and palatal components. Models I through IV focused on distalization.Models V and VI were created by adding expansions to Models III and IV. The displacement amounts, clear aligner deformations, and stress distributions were analyzed using Ansys 19.2. Results: The presence of a third molar reduced maximum total displacement by 17%. Models I and III demonstrated similar distal displacement and tipping, both of which were more pronounced than in Model IV. Model IV achieved the most parallel tooth movement, with the least distal and buccal tipping and minimal distopalatal rotation. In the comparison of Models V and VI, Model VI exhibited greater distal and buccal displacements and more tipping than Model V. Conclusions The presence of a third molar reduced distalization efficiency and increased clear aligner deformation. For both movements, the attachment that provided the most parallel movement showed the least displacement. When selecting attachments, it is essential to consider factors such as tooth rotation, inclination, bone support, and root health.

Objective: This study aimed to evaluate the effects of attachment design on maxillary molar distalization and simultaneous expansion during distalization, and the influence of third molars on distalization in the clear aligner technique using the finite element method. Methods: Six models were created to evaluate three different attachment designs on the second molars. Model I: employed a vertical rectangular attachment; Model II: used a vertical rectangular attachment with the presence of the third molar; Model III: used a combined semi-elliptical attachment; and Model IV: featured an opposed semi-elliptical attachment with buccal and palatal components. Models I through IV focused on distalization.Models V and VI were created by adding expansions to Models III and IV. The displacement amounts, clear aligner deformations, and stress distributions were analyzed using Ansys 19.2. Results: The presence of a third molar reduced maximum total displacement by 17%. Models I and III demonstrated similar distal displacement and tipping, both of which were more pronounced than in Model IV. Model IV achieved the most parallel tooth movement, with the least distal and buccal tipping and minimal distopalatal rotation. In the comparison of Models V and VI, Model VI exhibited greater distal and buccal displacements and more tipping than Model V. Conclusions The presence of a third molar reduced distalization efficiency and increased clear aligner deformation. For both movements, the attachment that provided the most parallel movement showed the least displacement. When selecting attachments, it is essential to consider factors such as tooth rotation, inclination, bone support, and root health.

OBJECTIVE: This study was performed to investigate the changes in alveolar bone after maxillary incisor intrusion and to determine the related factors in deep-bite patients. METHODS: Fifty maxillary central incisors of 25 patients were evaluated retrospectively. The maxillary incisors in Group I (12 patients; mean age, 16.51 ± 1.32 years) were intruded with a base-arch, while those in Group II (13 patients; mean age, 17.47 ± 2.71 years) were intruded with miniscrews. Changes in the alveolar envelope were assessed using pre-intrusion and post-intrusion cone-beam computed tomography images. Labial, palatal, and total bone thicknesses were evaluated at the crestal (3 mm), midroot (6 mm), and apical (9 mm) levels. Buccal and palatal alveolar crestal height, buccal bone height, and the prevalence of dehiscence were evaluated. Two-way repeated measure ANOVA was used to determine the significance of the changes. Pearson's correlation coefficient analysis was performed to assess the relationship between dental and alveolar bone measurement changes. RESULTS: Upper incisor inclination and intrusion changes were significantly greater in Group II than in Group I. With treatment, the alveolar bone thickness at the labial bone thickness (LBT, 3 and 6 mm) decreased significantly in Group II (p < 0.001) as compared to Group I. The LBT change at 3 mm was strongly and positively correlated with the amount of upper incisor intrusion (r = 0.539; p = 0.005). CONCLUSIONS: Change in the labial inclination and the amount of intrusion should be considered during upper incisor intrusion, as these factors increase the risk of alveolar bone loss.
Alveolar Bone Loss ; Cone-Beam Computed Tomography ; Humans ; Incisor* ; Overbite ; Prevalence ; Retrospective Studies